diff options
Diffstat (limited to 'fs/overlayfs/super.c')
-rw-r--r-- | fs/overlayfs/super.c | 66 |
1 files changed, 64 insertions, 2 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index fea7bd496f2e..fa83b3245124 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -34,6 +34,11 @@ module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); MODULE_PARM_DESC(ovl_redirect_dir_def, "Default to on or off for the redirect_dir feature"); +static bool ovl_index_def = IS_ENABLED(CONFIG_OVERLAY_FS_INDEX); +module_param_named(index, ovl_index_def, bool, 0644); +MODULE_PARM_DESC(ovl_index_def, + "Default to on or off for the inodes index feature"); + static void ovl_dentry_release(struct dentry *dentry) { struct ovl_entry *oe = dentry->d_fsdata; @@ -203,6 +208,7 @@ static void ovl_put_super(struct super_block *sb) struct ovl_fs *ufs = sb->s_fs_info; unsigned i; + dput(ufs->indexdir); dput(ufs->workdir); ovl_inuse_unlock(ufs->workbasedir); dput(ufs->workbasedir); @@ -265,6 +271,12 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) return err; } +/* Will this overlay be forced to mount/remount ro? */ +static bool ovl_force_readonly(struct ovl_fs *ufs) +{ + return (!ufs->upper_mnt || !ufs->workdir); +} + /** * ovl_show_options * @@ -286,6 +298,9 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) if (ufs->config.redirect_dir != ovl_redirect_dir_def) seq_printf(m, ",redirect_dir=%s", ufs->config.redirect_dir ? "on" : "off"); + if (ufs->config.index != ovl_index_def) + seq_printf(m, ",index=%s", + ufs->config.index ? "on" : "off"); return 0; } @@ -293,7 +308,7 @@ static int ovl_remount(struct super_block *sb, int *flags, char *data) { struct ovl_fs *ufs = sb->s_fs_info; - if (!(*flags & MS_RDONLY) && (!ufs->upper_mnt || !ufs->workdir)) + if (!(*flags & MS_RDONLY) && ovl_force_readonly(ufs)) return -EROFS; return 0; @@ -317,6 +332,8 @@ enum { OPT_DEFAULT_PERMISSIONS, OPT_REDIRECT_DIR_ON, OPT_REDIRECT_DIR_OFF, + OPT_INDEX_ON, + OPT_INDEX_OFF, OPT_ERR, }; @@ -327,6 +344,8 @@ static const match_table_t ovl_tokens = { {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, {OPT_REDIRECT_DIR_ON, "redirect_dir=on"}, {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"}, + {OPT_INDEX_ON, "index=on"}, + {OPT_INDEX_OFF, "index=off"}, {OPT_ERR, NULL} }; @@ -399,6 +418,14 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) config->redirect_dir = false; break; + case OPT_INDEX_ON: + config->index = true; + break; + + case OPT_INDEX_OFF: + config->index = false; + break; + default: pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); return -EINVAL; @@ -417,6 +444,7 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) } #define OVL_WORKDIR_NAME "work" +#define OVL_INDEXDIR_NAME "index" static struct dentry *ovl_workdir_create(struct super_block *sb, struct ovl_fs *ufs, @@ -610,6 +638,15 @@ static int ovl_lower_dir(const char *name, struct path *path, if (ovl_dentry_remote(path->dentry)) *remote = true; + /* + * The inodes index feature needs to encode and decode file + * handles, so it requires that all layers support them. + */ + if (ofs->config.index && !ovl_can_decode_fh(path->dentry->d_sb)) { + ofs->config.index = false; + pr_warn("overlayfs: fs on '%s' does not support file handles, falling back to index=off.\n", name); + } + return 0; out_put: @@ -807,6 +844,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) goto out; ufs->config.redirect_dir = ovl_redirect_dir_def; + ufs->config.index = ovl_index_def; err = ovl_parse_opt((char *) data, &ufs->config); if (err) goto out_free_config; @@ -965,6 +1003,13 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) } else { vfs_removexattr(ufs->workdir, OVL_XATTR_OPAQUE); } + + /* Check if upper/work fs supports file handles */ + if (ufs->config.index && + !ovl_can_decode_fh(ufs->workdir->d_sb)) { + ufs->config.index = false; + pr_warn("overlayfs: upper fs does not support file handles, falling back to index=off.\n"); + } } } @@ -1002,6 +1047,21 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) else if (ufs->upper_mnt->mnt_sb != ufs->same_sb) ufs->same_sb = NULL; + if (!(ovl_force_readonly(ufs)) && ufs->config.index) { + ufs->indexdir = ovl_workdir_create(sb, ufs, workpath.dentry, + OVL_INDEXDIR_NAME, true); + err = PTR_ERR(ufs->indexdir); + if (IS_ERR(ufs->indexdir)) + goto out_put_lower_mnt; + + if (!ufs->indexdir) + pr_warn("overlayfs: try deleting index dir or mounting with '-o index=off' to disable inodes index.\n"); + } + + /* Show index=off/on in /proc/mounts for any of the reasons above */ + if (!ufs->indexdir) + ufs->config.index = false; + if (remote) sb->s_d_op = &ovl_reval_dentry_operations; else @@ -1009,7 +1069,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) ufs->creator_cred = cred = prepare_creds(); if (!cred) - goto out_put_lower_mnt; + goto out_put_indexdir; /* Never override disk quota limits or use reserved space */ cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); @@ -1058,6 +1118,8 @@ out_free_oe: kfree(oe); out_put_cred: put_cred(ufs->creator_cred); +out_put_indexdir: + dput(ufs->indexdir); out_put_lower_mnt: for (i = 0; i < ufs->numlower; i++) mntput(ufs->lower_mnt[i]); |